1. Field of the Invention
The present invention relates to a semiconductor device using a MEMS (micro electro mechanical systems) technology (which will be referred to as a MEMS component hereinafter).
2. Description of the Related Art
The MEMS technology is a technology which finely manufactures a movable three-dimensional structure (moving part) by applying a semiconductor processing technique.
According to the MEMS technology, there is the possibility of developing a small high-performance component which is beyond comparison with existing components. For example, dramatically reducing a packaging dimension and greatly decreasing a power consumption by realizing integration of, e.g., an LSI and an individual component are no dream.
At present, as the MEMS components, a variable capacity, a switch, an acceleration sensor, a pressure sensor, an RF (radio frequency) filter, a gyroscope, a mirror device and others are mainly studied and developed (e.g., U.S. Pat. No. 6,355,498, U.S. Pat. No. 6,359,374, Jpn. Pat. Appln. KOKAI No. 2003-117897).
When translating these components into practical applications, however, there are still many problems which must be solved in terms of the reliability, a process yield, a manufacturing cost and others.
In relation to the reliability and a process yield, there is a problem of the strength of the MEMS component. For example, when water (H2O) enters a cavity which serves as a movable area of a moving part at the time of dicing, the MEMS component may be destroyed by a pressure of water in some cases. Therefore, in order to put the MEMS component to practical use, a technique which protects the MEMS component from such immersion of water and improves the reliability and a process yield must be developed.
In regard to a manufacturing cost, the development of a process technique which can realize the high reliability and a high process yield while decreasing the number of steps is a key point. However, when a so-called wafer level packaging technique which seals a cavity by attaching two wafers is adopted in order to protect the MEMS component from the above-described immersion of water, there is a problem in which the production steps become complicated, a manufacturing cost is increased and a chip size becomes large.